Abstract: A diffractive optical element includes a unit structure periodically arranged in a first direction and configured to diffract incident light in the first direction. The diffractive optical element has a phase pattern designed such that an angular separation between an outermost diffracted light beam and a second-outermost diffracted light beam along the first direction is smaller than the divergence angle of the incident light.

Abstract: An optical scanner includes: a light source; a deflection element including a plurality of pixels arranged one-dimensionally or two-dimensionally; a one-cycle diffraction grating including, among the pixels, continuous N pixels, where N is a natural number of two or more; the one-cycle diffraction grating having a length d in the alignment direction that is smaller than a wavelength ? of the light emitted from the light source; and a phase modulation controller configured to control a phase modulation amount of each of the pixels. Incident light is emitted from the light source obliquely from the reflecting surface at an incident angle ?1. Sin ?i+(?/d)>1 or sin ?i?(?/d)>1 is satisfied.

Abstract: An optical circuit for estimating separation distances between N image sources includes an aperture for receiving N light beams and producing a point spread function specific to a symmetry of the image sources from the plurality of light beams; first optical phase shifters to shift the quantum state modes of (N-1) light beams by NN; first beamsplitters, each for mixing respective pairs of quantum state modes of outputs of the first optical phase shifters for a quantum superposition of the respective pairs of the quantum state modes; second beamsplitters, each for mixing respective outputs of the first beamsplitters alternatively; second phase shifters to further shift outputs of the second beamsplitters; N detectors for converting each of the received N light beams to an analog signal; and a signal processing circuit for performing signal processing on the analog signals to estimate the separation distances.

Abstract: Aspects of the disclosure relate to methods, apparatus, and systems for oscillating transparent digital displays to generate a three-dimensional (3D) holographic image. A holographic imaging system includes a plurality of digital screens, wherein each screen of the plurality of digital screens is positioned parallel to an x-axis and a y-axis, and the screens are stacked along a z-axis perpendicular to the x-axis and the y-axis, a propulsion system configured to oscillate the plurality of digital screens along the z-axis, and a control system. The control system is configured to generate a digital image, display different slices of the digital image on the plurality of digital screens, and activate the propulsion system to oscillate the plurality of digital screens in synchronization with the display of the different slices on the screens to generate a three-dimensional (3D) image.

Abstract: Techniques of generating a wavefront modulating element (WME) for imaging an object over a large image field include (i) designing a WME by breaking a large image into smaller sub-images and then applying an inverse imaging operation to find a segment of a plurality of segments (324-1 to-334-n) of a WME (in the from of DOE) producing a sub-image, and (ii) specifying an optical system to illuminate the WME resulting from each of the plurality of segments in such a way that the large image is reproduced as closely as possible. Along these lines, given a large target image in the far-field, a WME generation system decomposes the target image into sub-images. From this decomposition, the WME generation system then produces WME segments corresponding to the sub-images.

Abstract: The present invention concerns an image conversion module (09) that comprises an optical interface (10) for establishing an optical path (07). The image conversion module (09) further comprises a beam splitting element (13) on the optical path (07). The beam splitting element (13) is configured for splitting a beam entering the optical interface (10, 11) on the optical path (07) into a first optical subpath (14) and a second optical subpath (16). The image conversion module (09) further comprises a microelectromechanical optical system (17) that is configured for enhancing a depth of field on the first optical subpath (14) that is directed to a first optoelectronic submodule (21). The image conversion module (09) further comprises a second optoelectronic submodule (24) having an electronic sensor (26) on the second optical subpath (16). The second optoelectronic submodule (24) is configured for acquiring additional data on the sample (02).

Abstract: Systems, devices, and methods for eyebox expansion in wearable heads-up displays (“WHUDs”) are described. The WHUDs described herein each include a projector and an optical waveguide positioned in an optical path between the projector and an eye of the user. For any given light signal from the projector, the optical waveguide receives the light signal at an input coupler and outputs multiple instances or copies of the light signal from multiple discrete, spatially-separated output couplers. The multiple instances or copies of the light signal may be converged by the optical waveguide directly to respective exit pupils at the user's eye or may be routed by the optical waveguide to a holographic combiner in the user's field of view from which the light signals may be converged to respective exit pupils at the user's eye. The optical waveguide employs exit pupil replication to expand the eyebox of the WHUD.

Abstract: Apparatus for powder-free intra-oral 3D imaging by using a projected texture pattern. A projector projects a random texture pattern of light to teeth to be imaged, and a digital image sensor receives the projected texture pattern from the teeth. The reflected pattern of light reflects and scatters from the teeth. The texture pattern can be a grid having clusters of bright and dark blocks in a pseudo-random arrangement and can provide for powder-free intra-oral 3D imaging by using the pattern to optically simulate powder applied to the teeth. Polarizers can be used in the optical path to transmit the directly reflected light to the image sensor and suppress or discard some of the unwanted scattered light.

Abstract: In various embodiments, alignment systems for laser resonators generate near-field and/or far-field images of input beams produced by the laser resonators to enable the alignment of the input beams.

Abstract: A functionalized waveguide for a detector system includes an incoupling region of a main body that deflects only part of the radiation coming from an object to be detected and impinges on the front face such that the deflected part propagates as coupled-in radiation in the main body by reflections up to the decoupling region and impinges on the decoupling region. A decoupling region deflects at least part of the coupled-in radiation impinging thereon such that the deflected part exits the main body via the front or rear face to impinge on the detector system. The extent of the incoupling region in a second direction transverse to the first direction is greater than the extent of the decoupling region in the second direction. In the second direction, the incoupling region has at least two different diffractive incoupling structures which have a different deflection component in the second direction.

Abstract: A system for generating an optical beam array includes a laser light source capable of generating a primary beam of light. An array generating optical element is capable of receiving the primary beam of light and splitting the primary beam of light into a beam array. The beam array can include at least two distinct pattern beams that divergently extend from the array generating optical element at a non-zero angle relative to one another. A void region is formed between the at least two pattern beams, the void region being devoid of any portion of the primary beam.

Abstract: An optical device (EPE1) comprises a waveguide plate (SUB1) comprising an in-coupling element (DOE1), a first expander element (DOE2a), a second expander element (DOE2b) and an out-coupling element (DOE3), wherein the out-coupling element (DOE3) is arranged to form combined output light (OUT1) by combining the first output light (OB3a) with the second output light (OB3b), wherein the in-coupling element (DOE1) has a first grating period (d1a) for forming the first guided light (B1a), and wherein the in-coupling element (DOE1) has a second different grating period (d1b) for forming the second guided light (B1b), wherein the optical device (EPE1) comprises a first spectral filter region (C2a) to prevent coupling of red light from the in-coupling element (DOE1) to the out-coupling element (DOE3) via the first expander element (DOE2a). The optical device (EPE1) can display a color image with an extended field of view.

Abstract: A display apparatus is disclosed for enabling a user to experience a 3D perception when visual information is presented by the display apparatus. The display apparatus has an image forming unit having a two-dimensional array of image subpixels arranged to emit light for presenting associated visual information, and an optical system having an array of diffractive optical elements associated with respective ones of the array of image subpixels. Each diffractive optical element is arranged to diffract light from the associated image subpixel into a diffraction pattern with a plurality of diffraction orders to provide the visual information from the associated image subpixel to a plurality of directional viewing regions associated with the plurality of diffraction orders.

Abstract: A design method of a diffractive optical assembly, and a diffractive optical assembly are provided. The design method comprises: designing a first diffractive optical element according to a target light field; simulating the first diffractive optical element to obtain a first light field difference between the simulation light field of the first diffractive optical element and the target light field; and designing a second diffractive optical element according to the first light field difference.

Abstract: A laser beam combining device includes an emission optical system that emits a plurality of circular laser beams propagated coaxially and having mutually different wavelengths, and a diffractive optical element that is concentric and diffracts the plurality of circular laser beams. The diffractive optical element diffracts the plurality of circular laser beams in accordance with the wavelengths of the circular laser beams, such that local diffraction angles of diffracted light of the plurality of circular laser beams incident at mutually different local incidence angles are equal to each other.

Abstract: A multi-functional diffractive optical element (DOE) for redirecting light into a waveguide and providing higher order aberration correction is described. The multi-functional DOE may be positioned on, connected to, adjacent to, or within a waveguide, and in some examples is positioned at, or near, the exit pupil of the projector lens. In an example, a head-mounted display (HMD) is configured to output artificial reality content, comprising a waveguide configured to receive input light and configured to output the received input light to an eyebox. The HMD further comprises a projector configured to input light into the waveguide, the projector comprising a display, a projection lens, and a multi-functional diffractive optical element (DOE) configured to redirect light from the projector into the waveguide and provide higher order aberration correction of the light from the display.

Abstract: A multi-waveguide optical structure, including multiple waveguides stacked to intercept light passing sequentially through each waveguide, each waveguide associated with a differing color and a differing depth of plane, each waveguide including: a first adhesive layer, a substrate having a first index of refraction, and a patterned layer positioned such that the first adhesive layer is between the patterned layer and the substrate, the first adhesive layer providing adhesion between the patterned layer and the substrate, the patterned layer having a second index of refraction less than the first index of refraction, the patterned layer defining a diffraction grating, wherein a field of view associated with the waveguide is based on the first and the second indices of refraction.

Abstract: An optical device comprises a waveguide plate, which in turn comprises: an in-coupling element to form first guided light and second guided light by diffracting input light, first expander element to form third guided light by diffracting the first guided light, second expander element to form fourth guided light by diffracting the second guided light, and an out-coupling element to form first output light by diffracting the third guided light, and to form second output light by diffracting the fourth guided light, wherein the out-coupling element is arranged to form combined output light by combining the first output light with the second output light, wherein the in-coupling element has a first grating period for forming the first guided light, and wherein the in-coupling element has a second different grating period for forming the second guided light.

Abstract: A LIDAR device for detecting an object comprising a transmitter unit having at least one laser for emitting at least one laser beam; and a receiver unit for receiving laser light that was reflected by the object. The transmitter unit further has at least one beam replication unit for replicating the at least one laser beam to form at least two replicated beams.

Abstract: An apparatus may include (1) a planar liquid-crystal structure including a plurality of liquid crystals, and (2) a plurality of electrodes coupled to the planar liquid-crystal structure such that (a) when a first plurality of voltages are applied to at least some of the plurality of electrodes, the plurality of liquid crystals are oriented such that the planar liquid-crystal structure operates as a diffraction grating having a first pitch, and (2) when a second plurality of voltages are applied to at least some of the plurality of electrodes, the plurality of liquid crystals are oriented such that the planar liquid-crystal structure operates as a diffraction grating having a second pitch different from the first pitch.

Abstract: The invention relates to a method for producing a support body in a card format, with a graphic customization, that has a surface finishing effect that is more or less smooth, rough, mirrored or matte on the support body. The method includes supplying a support body having a layer of material configured to allow a marking by punching or lamination. The layer is exposed on the main external face and the surface finishing effect is equivalent to that obtained by a step of marking or lamination while not including a step of depositing varnish.

Abstract: An optical device according to an embodiment of the present disclosure includes a light source in which a plurality of light emitting elements are arranged at a predetermined distance, an optical system configured to convert light beams from the plurality of light emitting elements into line light beams, and a light deflection element configured to deflect each of the line light beams. Each of the line light beams is caused to be incident on the light deflection element such that a longitudinal direction of each of the light beams is aligned with a direction of a rotating axis of the light deflection element.

Abstract: The present invention relates to an optically variable security element for securing valuable articles, having a substrate having opposing first and second main surfaces and, arranged on the first main surface, an optically variable pattern that comprises an embossing pattern and a coating. The coating comprises at least one imprinted line grid and a background layer that contrasts with the line grid. The embossing pattern comprises a two-dimensional grid of elevated and/or depressed embossing elements. Both are combined in such a way that substantially on every embossing element lies at least one line segment of a line in the line grid, and at least one of the parameters position of the line segment on the embossing element, orientation of the line segment on the embossing element and form of the line segment varies location dependently across the dimension of the optically variable pattern.

Abstract: An observation optical system according to the present invention includes a Fresnel lens and a lens LP with a positive refractive power provided on a light incident side or a light emitting side of the Fresnel lens. A length in a direction of an optical axis from a surface vertex of a central annular section of the Fresnel lens to an end portion of the central annular section is defined as h0, and a length in the direction of the optical axis of a grating wall surface of a first annular section adjacent to the central annular section is defined as h1. The lengths h1 and h0 are set to appropriate values, respectively.

Abstract: A lens module includes a diffractive optical element, a lens, and a plurality of positioning elements, the diffractive optical element and the lens are matched and positively held together. First positioning grooves are defined in the diffractive optical element, and corresponding second positioning grooves are defined in the lens which is stacked on the diffractive optical element. Each positioning element is fixed in and entirely within a first positioning groove and a second positioning groove to fix and hold the diffractive optical element and the lens together.

Abstract: In various embodiments, alignment systems for laser resonators generate near-field and/or far-field images of input beams produced by the laser resonators to enable the alignment of the input beams.

Abstract: A zoom lens L0 includes a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, a third lens unit L3 having a positive refractive power, an intermediate lens group LM including a plurality of lens units, and a last lens unit LR having a negative refractive power. An interval between the adjacent lens units changes during zooming. The zoom lens L0 includes an aperture stop SP. The intermediate lens group LM includes a negative lens unit LN having a negative refractive power. Both the negative lens unit LN and the last lens unit LR move to an object side during zooming from a wide-angle end to a telephoto end. The zoom lens L0 satisfies predetermined conditional inequalities.

Abstract: A rotatable optical module able to aim structured light in different directions includes a driver and an optical assembly positioned at a side of the driver and connected to the driver. The optical assembly projects structured light. The driver drives the optical assembly to rotate, thereby changing the aiming direction of the structured light. An electronic device using such module and placed directly between two target objects is able to function as a meter of the distance between the objects in addition to mapping the contours of each.

Abstract: A method of forming an article which includes a diffraction grating, an article, and an apparatus for forming the article by printing are described. The method includes forming a periodic structure by printing a first set of parallel lines on a first side of a transparent substrate with a marking material and printing a second set of parallel lines on a second side of the transparent substrate with a marking material, the first and second sets of lines, in combination, defining a grating having a frequency and a spacing between lines which causes incident light to be diffracted into a plurality of beams travelling in different directions.

Abstract: An ocular optical system for imaging of imaging rays entering an eye of an observer via the ocular optical system from a display screen is provided. A side facing towards the eye is an eye-side, and a side facing towards the display screen is a display-side. The ocular optical system includes a first lens element, a second lens element, and a third lens element from the eye-side to the display-side in order along an optical axis. The first lens element, the second lens element, and the third lens element each include an eye-side surface and a display-side surface. Lens elements having refracting power of the ocular optical system are only the first lens element, the second lens element, and the third lens element.

Abstract: A multilayered optical security device has a resonant waveguide grating (RWG) layer on an under layer having a hologram. The RWG layer has plural RWGs for generating one or more patterns. Each RWG has first and second RWG portions, with diffraction gratings of different grating periods, for light coupling-in and coupling-out, respectively. Using the RWGs minimizes interference to a holographic image generated by the under layer. This advantage is especially useful when the holographic image carries digital data such as in digital holographic encryption where an encrypted hologram is used in the under layer. The digital data may contain biometric information such as a fingerprint. In each RWG portion of an individual RWG, scattering elements in a grating are curved to thereby enhance an angular tolerance in azimuthal angle during observing the patterns by an observer while the individual RWG is still selective in elevation angle.

Abstract: Provided are a highly versatile counterfeit-preventive optical element applicable to both the banknote field and the ID field and an information medium including the optical element. A counterfeit-preventive optical element (1) of an embodiment includes a first layer (2), second layer (3), and a third layer (6) that are stacked in this order. A relief structure (R) is provided between the first layer (2) and the second layer (3), the first layer (2) includes a first region (4) and a second region (5), the first region (4) totally reflects incident light incident from the first layer (2) due to at least one of the angle of a face of the relief structure (R) and the refractive index ratio of the first layer (2) and the second layer (3), and the second region (5) transmits or refracts at least some of incident light incident from the first layer (2) due to one of the angle of a face of the relief structure (R) and the refractive index ratio of the first layer (2) and the second layer (3).

Abstract: A device for forming at least one focused beam in a near-field zone, from an electromagnetic wave incident on the device, is remarkable in that it comprises at least one layer of dielectric material comprising at least partially at least one cavity, the at least one cavity being filled in with a medium having a refractive index lower than that of the dielectric material. The at least one cavity is targeted to be cylindrical or cone-shaped and comprises at least one base surface, defined with respect to an arrival direction of the electromagnetic wave, and at least one lateral surface.

Abstract: A composition for a high refractive index, low dispersion resin for a close-contact double layer-type composite diffractive optical element that is highly photocurable and provides a high productivity, and a close-contact double layer-type composite diffractive optical element using such composition are provided. A composition for a high refractive index, low dispersion resin for a close-contact double layer-type composite diffractive optical element includes a thiol compound represented by general formula (1) or an oligomer synthesized by use of a thiol compound represented by general formula (1) (A component); and an ene compound including two or more polymerizable unsaturated bonds (B component). (In the formula, p represents an integer of 2 to 5; Xp and Zp independently represent a hydrogen atom or a mercaptomethyl group; a ratio of sulfur atoms in a molecule is 40 to 80% by mass; and the number of thiol groups is 3 or larger.).

Abstract: An iris image acquisition system for a mobile device, comprises a lens assembly arranged along an optical axis and configured for forming an image comprising at least one iris of a subject disposed frontally to the lens assembly; and an image sensor configured to acquire the formed image. The lens assembly comprises a first lens refractive element and at least one second lens element for converging incident radiation to the first refractive element. The first refractive element has a variable thickness configured to counteract a shift of the formed image along the optical axis induced by change in iris-lens assembly distance, such that different areas of the image sensor on which irises at different respective iris-lens assembly distances are formed are in focus within a range of respective iris-lens assembly distances at which iris detail is provided at sufficient contrast to be recognised.

Abstract: A head-up display for a vehicle includes: a display panel, a deflector having a plurality of microlenses, and an image generator. The image generator is configured to generate a plurality of primary elementary images which are multiplied by an optical multiplier into elementary images, which are in turn assigned in each case to a respective one of the plurality of microlenses.

Abstract: An integrated optical beam steering device includes a planar dielectric lens that collimates beams from different inputs in different directions within the lens plane. It also includes an output coupler, such as a grating or photonic crystal, that guides the collimated beams in different directions out of the lens plane. A switch matrix controls which input port is illuminated and hence the in-plane propagation direction of the collimated beam. And a tunable light source changes the wavelength to control the angle at which the collimated beam leaves the plane of the substrate. The device is very efficient, in part because the input port (and thus in-plane propagation direction) can be changed by actuating only log2 N of the N switches in the switch matrix. It can also be much simpler, smaller, and cheaper because it needs fewer control lines than a conventional optical phased array with the same resolution.

Abstract: A transmission structure includes a plurality of first transmission units and a plurality of second transmission units. A transmission phase of an electromagnetic wave of the second transmission unit is equal or similar to a transmission phase of an electromagnetic wave of the first transmission unit. A reflection phase of the electromagnetic wave of the second transmission unit is different from a reflection phase of the electromagnetic wave of the first transmission unit. The plurality of first transmission units and the plurality of second transmission units are arranged disorderly on a surface.

Abstract: A diffractive optical beam shaping element for imposing a phase distribution on a laser beam that is intended for laser processing of a material includes a phase mask that is shaped as an area and is configured for imposing a plurality of beam shaping phase distributions on the laser beam incident on to the phase mask. A virtual optical image is attributed to at least one of the plurality of beam shaping phase distributions, wherein the virtual image can be imaged into an elongated focus zone for creating a modification in the material to be processed. Multiple such elongated focus zones can spatially add up and interfere with each other, to modify an intensity distribution in the material and, for example, generate an asymmetric modification zone.

Abstract: A low-height projector assembly includes a biconvex lens, a converging lens, an aperture stop, and a beam-steerer between the biconvex lens and the converging lens. The biconvex lens has a principal plane, a focal length, and a first optical axis. The converging lens has a second optical axis laterally offset from the first. The beam-steerer is configured to steer light from the biconvex lens to the converging lens. An aperture-stop plane intersects the second optical axis and the aperture stop. On the second optical axis, at least one of a front surface and a back surface of the converging lens is between the aperture-stop plane and the beam-steerer. The axial chief ray's propagation distance from the principal plane to the aperture stop differs from the focal length by less than half the depth of focus of the biconvex lens.

Abstract: Techniques are described in which a decoder is configured to receive an input data block and apply an inverse non-separable transform to at least part of the input data block to generate an inverse non-separable transform output coefficient block. The applying the inverse non-separable transform comprises assigning a window, assigning a weight for each position inside the assigned window, and determining the inverse non-separable transform output coefficient block based on the assigned weights. The decoder is further configured to forming a decoded video block based on the determined inverse non-separable transform output coefficient block, wherein forming the decoded video block comprises summing the residual video block with one or more predictive blocks.

Abstract: The invention relates to a diffractive optical grating and applications thereof. The grating comprises a first zone and a second zone each having a two-dimensionally periodic grating structure having a first period (dx) in a first direction, the first period being chosen to allow for diffraction of selected wavelengths of visible light along the first direction, and a second period (dy) in a second direction different from the first direction, the second period (dy) being short enough to prevent diffraction of said selected wavelengths along the second direction. According to the invention, the grating structures in the first zone and in the second zone have different modulation characteristics in said second direction for producing different diffraction efficiencies for the first and second zones. The invention provides a new design parameter, sub-wavelength modulation, for assisting in local adjustment of diffraction efficiency of gratings in particular in display applications.

Abstract: A waveguide display includes light sources, a source waveguide, an output waveguide, and a controller. Light from each of the light sources is coupled into the source waveguide. The source waveguide includes gratings with a constant period determined based on the conditions for total internal reflection and first order diffraction of the received image light. The emitted image light is coupled into the output waveguide at several entrance locations. The output waveguide outputs expanded image lights at a location offset from the entrance location, and the location/direction of the emitted expanded image light is based in part on the orientation of the light sources. Each of the expanded image light is associated with a field of view of the expanded image light emitted by the output waveguide.

Abstract: A light flux diameter expanding element includes a light guiding plate with a light input face and a light output face, and with a thickness of 0.2 mm to 0.8 mm; a diffraction grating on the input side; and a diffraction grating on the output side, and is provided so as to have the same grating period as that of the diffraction grating on the input side, in which a forming region of the diffraction grating on the input side is smaller than that of the output side, and a grating period of the diffraction grating on the input side is a period in which a small diffraction angle in diffraction angles of +1-st order diffracted light and ?1-st order diffracted light, which are diffracted in the diffraction grating on the input side, in the light guiding plate becomes larger than a critical angle of the light guiding plate.

Abstract: A lens assembly includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens are arranged in order from an object side to an image side along an optical axis. The first lens has negative refractive power. The second lens has positive refractive power. The third lens has negative refractive power and includes a convex surface facing the image side. The fourth lens has positive refractive power and includes a concave surface facing the object side. The fifth lens has positive refractive power and includes a concave surface facing the image side.

Abstract: Multiple cameras are coupled to a camera rig. Multiple diffractive optical elements (DOEs) are coupled to a DOE prop. Each camera is positioned in an eye box of a DOE and takes an image when the cameras are positioned at a first position, a second position and a third position relative to the DOEs. Three images taken by a each camera at each one of the first position, the second position and third position. The images are transmitted to a processor coupled to the camera rig. For each image, the processor identifies data pairs, each data pair including pixel coordinates of an intensity peak in the image and virtual light source produced by the diffractive optical element that corresponds to the intensity peak, and determines extrinsic parameters of the cameras using the identified data pairs for each image.

Abstract: There is provided a diffraction optical element which comprises a base material, and in which a first resin layer having a diffraction grating shape and a second resin layer are laminated on the base material. The diffraction grating shape forms a plurality of concentric annular sections when planarly viewed from a lamination direction of the diffraction optical element. The second resin layer comprises a first portion and a second portion, and the first portion is provided on a first annular section of the first resin layer. The second portion is continuously provided from above the first portion to above a region including a periphery of the first resin layer. A difference between a refractive index of the second portion on a center of the first annular section and a refractive index of the second portion on a circumference of the first annular section is within 0.0005.

Abstract: Apparatus for structured light scanning. The structured light includes one or more projected lines or other patterns. At least two independent emitters emit light for each projected line or pattern. Typically the at least two independent emitters are arranged in a row. The apparatus also includes a pattern generator for causing light from respective emitters of a given row to overlap along a pattern axis to form a projected pattern.

Abstract: A device and method for obtaining depth information from a light field is provided. The method generating a plurality of epipolar images from a light field captured by a light field acquisition device; an edge detection step for detecting, in the epipolar images, edges of objects in the scene captured by the light field acquisition device; for each epipolar image, detecting valid epipolar lines formed by a set of edges; and determining the slopes of the valid epipolar lines. In a preferred embodiment, the method extend the epipolar images with additional information of images captured by additional image acquisition devices and obtain extended epipolar lines. The edge detection step calculates a second spatial derivative for each pixel of the epipolar images and detects the zero-crossings of the second spatial derivatives.

Abstract: A near eye optical display includes a waveguide comprising a first surface and a second surface, an input coupler, a fold grating, and an output grating. The input coupler is configured to receive collimated light from a display source and to cause the light to travel within the waveguide via total internal reflection between the first surface and the second surface to the fold grating; the fold grating is configured to provide pupil expansion in a first direction and to direct the light to the output grating via total internal reflection between the first surface and the second surface; and the output grating is configured to provide pupil expansion in a second direction different than the first direction and to cause the light to exit the waveguide from the first surface or the second surface.